Trona ore is mined and calcined for use in the manufacture of sodium carbonate, which in turn can be used to make sodium bicarbonate (NaHCO.sub.3), a valuable product. The naturally occurring trona ore material generally has the formula Na.sub.3 H(CO.sub.3).sub.2. 2H.sub.2 O, and is characterized as a hydroxyacid sodium carbonate. Trona is found in, or contiguous to, oil shale, and thus contains large amounts of organics, which it is desirable to remove from the sodium carbonate product. Unfortunately, insoluble organic and inorganic materials are contiguous in the trona ore, and are not easily separated. These impurities impact the characteristics of the final soda ash produced.
The processes used to produce soda ash from crude trona ore include various steps of calcination, dissolution of the converted soda ash to concentrated liquor, solids/liquids separation steps, filtration and/or purification, evaporation/crystallization, and drying the monohydrate formed to anhydrous soda ash for industrial use.
In accordance with the present commercial process, the crushed and calcined trona ore is treated with water to dissolve the soluble sodium carbonate product. The resultant liquid solution, or liquor, is clarified, decanted and then filtered to remove the solids. Treatment of the solution with activated carbon may follow to remove some portion of the organic materials. However, treatment with activated carbon is expensive. In addition to the high costs of the activated carbon itself, there are several auxiliary processing costs; the carbon must be filtered out after the carbon is sufficiently inactivated, requiring additional manpower, testing and filtering equipment, and the spent carbon must be disposed of, which is also expensive.
After the carbon treatment step, when used, the liquor is evaporated to obtain a crystallized sodium carbonate product. Antifoam agents are often added during this step to prevent foaming that would foul condensing liquids. These liquids are re-used as pure water when clean enough.
When the sodium carbonate product is to be used to make sodium bicarbonate, the anhydrous soda ash is dissolved in water and the resultant sodium carbonate solution is then reacted with carbon dioxide to form sodium bicarbonate in accordance with the following reaction: EQU Na.sub.2 CO.sub.3 +CO.sub.2 +H.sub.2 O.fwdarw.2NaHCO.sub.3
However, even if treated with activated carbon, objectionably some organic materials from the anhydrous soda ash are passed on to the sodium bicarbonate process. This residual organic material interferes with the ability of the soda ash to react with carbon dioxide.
Thus considerable engineering skill is needed to maximize the carbon dioxide adsorption efficiency of sodium carbonate and the rate of sodium bicarbonate crystal formation from sodium carbonate. An improved method for modifying the sodium carbonate source that enhances the carbonation reaction would be highly advantageous.